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<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>标识符</title>
</head>
<body>
<script>
    /* 在js中所有我们可以自主命名的都可以是标识符，如变量名，函数名 属性名等
     *  标识符命名的规则:
     *      1.可以是字母 、数字、 _ 、$
     *      2.不能以数字开头
     *      3.标识符不能是ES中的关键字或保留字  ECMAScript是标准
     *      4.标识符一般采用驼峰命名法
     *              首字母小写以后每个字母的首字母大些，其余的字母小写
     *      5.JS底层保存标识符时 实际上是采用的Unicode编码 理论上讲UTF-8中含有的内容都可以做为标识符
     */
    var ab_1$=334455;
    console.log(ab_1$);//返回334455

    var helloWorld=50000;
    console.log(helloWorld);//返回50000

    // var 锄禾日当午=789556;  不建议使用
    // console.log(锄禾日当午);//返回789556
</script>
    <table border="1" cellspacing="0" cellpadding="5">
        <caption><h3>关键字</h3></caption>
        <tr align="center">
            <td>break</td>
            <td>do</td>
            <td>instanceof</td>
            <td>typeof</td>
            <td>case</td>
        </tr>
        <tr align="center">
            <td>else</td>
            <td>new</td>
            <td>var</td>
            <td>catch</td>
            <td>finally</td>
        </tr>
        <tr align="center">
            <td>retrun</td>
            <td>void</td>
            <td>continue</td>
            <td>for</td>
            <td>swich</td>
        </tr>
        <tr align="center">
            <td>while</td>
            <td>default</td>
            <td>if</td>
            <td>throw</td>
            <td>delete</td>
        </tr>
        <tr align="center">
            <td>in</td>
            <td>try</td>
            <td>function</td>
            <td>this</td>
            <td>with</td>
        </tr>
        <tr align="center">
            <td>debugger</td>
            <td>false</td>
            <td>true</td>
            <td>null</td>
            <td></td>
        </tr>
    </table>
    <table border="1" cellspacing="0" cellpadding="6">
        <caption><h3>保留字</h3></caption>
        <tr align="center">
            <td>class</td>
            <td>enum</td>
            <td>extends</td>
            <td>const</td>
            <td>export</td>
            <td>super</td>
        </tr>
        <tr align="center">
            <td>import</td>
            <td>implements</td>
            <td>private</td>
            <td>public</td>
            <td>yield</td>
            <td>let</td>
        </tr>
        <tr align="center">
            <td>interface</td>
            <td>package</td>
            <td>protected</td>
            <td>static</td>
            <td></td>
            <td></td>
        </tr>
    </table>
    <table border="1" cellpadding="6" cellspacing="0">
        <caption><h3>其他不建议使用的标识符</h3></caption>
        <tr align="center">
            <td>abstract</td>
            <td>double</td>
            <td>goto</td>
            <td>native</td>
            <td>static</td>
            <td>boolean</td>
        </tr>
        <tr align="center">
            <td>enum</td>
            <td>implements</td>
            <td>package</td>
            <td>super</td>
            <td>byte</td>
            <td>export</td>
        </tr>
        <tr align="center">
            <td>import</td>
            <td>private</td>
            <td>synchronize</td>
            <td>char</td>
            <td>entends</td>
            <td>int</td>
        </tr>
        <tr align="center">
            <td>protected</td>
            <td>throws</td>
            <td>class</td>
            <td>final</td>
            <td>interface</td>
            <td>public</td>
        </tr>
        <tr align="center">
            <td>transient</td>
            <td>const</td>
            <td>float</td>
            <td>long</td>
            <td>short</td>
            <td>volatile</td>
        </tr>
        <tr align="center">
            <td>arguments</td>
            <td>encodeURI</td>
            <td>infinity</td>
            <td>Numner</td>
            <td>RegExp</td>
            <td>undefined</td>
        </tr>
        <tr align="center">
            <td>inFinite</td>
            <td>Object</td>
            <td>String</td>
            <td>Boolean</td>
            <td>Error</td>
            <td>RangeError</td>
        </tr>
        <tr align="center">
            <td>parseFloat</td>
            <td>SyntaxError</td>
            <td>Date</td>
            <td>eval</td>
            <td>JSON</td>
            <td>ReferenceError</td>
        </tr>
        <tr align="center">
            <td>TypeError</td>
            <td>decodeURI</td>
            <td>EvalError</td>
            <td>Math</td>
            <td>URIError</td>
            <td>decodeURIComponent</td>
        </tr>
        <tr align="center">
            <td>Function</td>
            <td>NanN</td>
            <td>isNAN</td>
            <td>parseInt</td>
            <td>Array</td>
            <td>encodeURICOmponent</td>
        </tr>
    </table>
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